5BT 130
2.5 Tightening Torques
DG and P (Plastoform) screws are used in polymer and light metal components. These screws form a
permanent thread when they are installed for the first time. They can be removed and installed as often as
necessary without impairing the strength of the screwed assembly, providing the specified tightening
torque is observed.
For this reason it is essential to use a torque wrench.
Use the following procedure when refitting a DG or P screw in an existing thread:
Insert the screw in the hole and rotate it counterclockwise until it drops down slightly and engages in the existing
thread. Tighten the screw clockwise to the specified torque.
This procedure ensures that the screw engages properly in the existing thread and does not form a new thread
and weaken the assembly.
Micro-encapsulated screws and screws coated with threadlocking adhesive:
Before re-installing, clean both threads (screw tap into female thread by hand and then blow out with
compressed air; clean male thread with brush), coat micro-encapsulated screws with medium-strength
Loctite 242 or 243 (see list of screws below).
Power screwdriver setting for polymer: P and DG screws max. 500 rpm.
Do not use an impact wrench for releasing or tightening screws.
Do not mix up screws with and without binding heads.
Fastener Thread size For component Torque
Nm
Remarks
Screw M 6x25 Cover washer/clutch shoe/flywheel 12.0 1), 2)
Screw D 4x18 Cover/engine pan 4.5 1), 2)
Screw P 4x16 Cover / spacer flange / push-on nut 0.8
Screw D 4x18 Cover/cylinder 4.5 1), 2)
Screw M 4x9.6 Spark arresting screen/muffler 2.0
Collar screw M 5x16 Rocker lever collar screw/cylinder 9.0 3)
Screw D 5x24 Engine pan/cylinder 9.0 1), 2)
Screw D 5x24 Fan housing/shroud/engine pan 6.0 1), 2)
Screw D 5x24 Fan housing/engine pan 6.0 1), 2)
Nut M 8x1 Flywheel / crankshaft 17.0 4)
Screw D 5x24 Starter cover/cover/engine pan 6.0 1), 2)
Screw D 5x24 Starter cover / fuel tank / engine pan 6.0 1), 2)
Nut M 8x1 Starter cup / crankshaft 17.0
Screw M 5x30 Valve cover/cylinder 3.5
M 10x1 Spark plug / cylinder 12.0
Screw D 4x18 Ignition module / cylinder
(1x with washer)
4.5 1), 2)
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